Chamber block



FIG. 1 is a front top perspective view of a chamber block which embodies the design;

FIG. 2 is a front bottom perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a right side view thereof; the left side view thereof being a mirror image of the right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view.

The structures depicted by means of broken lines in the figures have been shown for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a chamber block, as shown and described. 